Electric control apparatus for fuel burners



March 17, 1936. A. L. RUBEL 2,034,311 .I

ELECTRIC coNTRoL APPARATUS Foa FUEL unimns Filed sept. 12, 1932 QURR ENT sUPPtY R'ooM THERMosTAT FuRNAc.: SWITCH I MEcHAmsM IGNITION SWITCH VALVE SWITCH OIL VA LY E conusnou www Patented Mar. 17, 193s UNITED STATES ELECTRIC CNTROL APPARATUS FOR FUEL BURNERS Abraham Lincoln Rubel, signor to Penn Electri c Switch Co.,

Des Moines, Iowa, as-

Dee Momes,

Iowa, a corporation of Iowa Application September 12 1932, Serial No. 632,710

2 Claims.

An object of my invention is to provide con trol apparatus for the electric circuit of a fuel burner, the apparatus being comparatively simple and inexpensive to manufacture.

A further object is to provide control apparatus for an electrically operated fuel burner with a means for introducing the fuel into the burner a predetermined period of time after ignition .has been initiated to thus get the-spark gap terminals well heated before atomized oil is blown over them and thereby to prevent carbonizing of the terminals.

Still a further object is to provide a switch for a fuel vaclve which is electro-responsive so that it can be operated by the ignition switch when it establishes the ignition circuit and yet which includes a circuit closing switch which is delayed in actionthat is, it does not close immediately but has a delayed closing action so that after the electro-responsive part of the switch has been energized, a predetermined lapse of time occurs 'before the switch is closed for opening the fuel valve.

Another object yis to provide a delayed action switch of the warp switch type in which the vwarp switch heater is connected in the circuit ci the ignition switch, the ignition switch being combustion responsive to open upon combustion occurring, provision being made for maintaining the circuit established through the warp switch to retain the fuel valve in open position after combustion occurs.

With these and other objects in View my invention consists in the construction, arrangement and combination of the various parts of my device, whereby the objects contemplated are attained, as hereinafter more fully set forth, point-r ed out in my claims, and illustrated in the accompanying drawing, in which:

The figure illustrates diagramma-tically my control apparatus for fuel burners and the electric circuit thereof.

Current is supplied to a line switch Ill, a fuse being indicated at I2. The current flows through contacts I4 and I6 of av safety switch, then through a junction box I8 to a furnace switch and from there to a terminal 2 of a junction box 20. From the terminal 2, the current is supplied to a relay coil and to a burner motor contact 22 on the armature 24 of the relay.

The other side of the line extends to the junction box I8 and branches therein to be supplied through one wire to a room thermostat and through another wire to a burner motor, its ignition mechanism, a warp switch heater 26 of an oil valve switch and an oil valve.

From the room thermostat, current is supplied through the junction box I8 to a terminal I in the junction box 20. From the terminal I, a wire extends to a holding contact 28 of the relay and to 'through the terminal a safety switch heater 30. The safety switch heater is controlled by a combustion switch having contacts 32 and 34. 'Ihe combustion switch is connected in circuit with the relay so that current through the combustion switch ows through the upper part of the winding of the coil and returns to the terminal 2.

For cooperation with the contact 22, I provide a contact 36 which is connected with the contact 38 of a combustion responsive ignition switch and also with a contact 48 of an oil valve switch and a, terminal 4 in the junction box 2Il.A i

A wire from the terminal 4 extends through the junction box I8 to the motor 42 of the burner.

An ignition contact .44 cooperates with the con- 15 tact 38. The contact 44 is connected with a terminal 3 in the junction box 2li and then extends through the junction box I8 and to the primary of the ignition mechanism for thus controlling it. The contact 44 is also connected with the warp switch heater 26. 'L

For cooperation with the contact 38, I provide a contact 46 which is connected with the oil valve and with the contact 48 of the oil valve switch: 2.5

Practical operatm In the operation of m`y control apparatus, when the room thermostat moves to closed circuit position because of the room temperature becom- 30 ing lowered to a predetermined minimum, a clrcuit is established through the safety switch heater 30, through the contacts 32 and 34, through ,the upper part of the coil of the relay,

2, through the furnace 35 switch contacts I6 and I4 andback to the line. (The furnace switch is provided to prevent an overrun of heat by opening upon a predetermined high temperature condition of the furnace 50.) Since the relay is now energized, the contacts 22 40 and 28 will be lowered into contact with a contact 35 and a contact 52,- respectively. The contact 52 is a holding contact so that the current from the room thermostat will flow through the contacts 28 and 52 and then through the entire relay 45 coil back through the terminal 2, the furnace switch and contacts I6, I4 to the line.

This is so that when combustion occurs and opens the combustion switch, the relay coil will not be de-energized. 50

Energization of the relay co-il also establishes a circuit through the contacts 22 and 36 to the ignition switch and through the contacts 38 and 44 thereof to the warp switch heater 26 and the ignition mechanism through the terminal 3 and 65 the junction box I8. This causes the heater 26v to heat and close the contacts 4I! and 48 after a predetermined period of time during which the ignition mechanism has been energized and ignition thereby establishedat the spark gap 54.

The closed contacts 22 and 36 also cause current to flow from the furnace switch through the terminal 2 to the terminal 4 and then to the burner motor 42 for causing it to operate simultaneously with igniter energization to thus get it up to speed for most eilicient atomiza-tion of the fuel when the fuel valve opens, after the delayed periodof time.

After the predetermined period of time mentioned, the contact 48 will engagethe contact 40 for energizing the solenoid 56 of the oil valve. This opens the valve so that oil or any fuel being used in the burner will be admitted to the burner.

After the oil valve is opened, the oilwill be ignited and thus cause operation of the combustion. switch and the ignition switch to the opposite position from the position shown. 'Ihis will open the contacts 32 and 3 4, as before stated and will open the contacts 38 and 44 for opening the ignition circuit and thus terminating the ignition operation.

As soon as the contact 38 leaves the contact 44, the heater 28 will be de-energlzed and after the oil valve switch has cooled to a certain extent, the contacts 40 and 48 will be separated. Before this occurs, however, the contact 38 has engaged the contact 46 for maintaining a circuit established through the solenoid 56 so that sep aration of 'the contacts 40 and 48 will not cut off the supply of current.

Upon the room thermostat being satisiled, the l holding circuit through the contacts 28 and 52 will be broken so that the relay -will open and terminate operation of the burner motor 42 and will permit the oil valve to close because of the contacts 22 and 36 becoming separated. The combustiony and ignition switches will then return to the normal positions shown on the drawing'when the combustion space of the furnace cools down.

In the event of combustion failure, the contacts 32V and 24 will be engaged for closing the circuits through the safety switch heater 30 so that the contact li willy leave the contact I4 after a predetermined period of time. The ignition switch, however, is arranged so that it will not reestablish ignition. This is done by providing an extension 58 on the relay armature 24 to spring an arm 60 and a leaf spring extension 8l thereof downwardly whenever the armature closes. The extension 6| is adapted to act as an obstruction behind a leaf spring contact carrier 39 of the ignition switch when the armature 24 jis drawn downwardly, so that the contact 38 can .leave the contact 48, but cannot re-engage the contact 44 and thus re-establish igniter energization until the safety switch has operated to open the entire circuit andvthereby permits the 'relay armature to return to normal position.

The circuit is then locked out by the safety switch until the cause of combustion failure has been determined and remedied`and the safety switch manually moved again to closed position. I have illustrated a shut down type of circuit, but my delayed oil valve can also be used with a purging type, both of,which are now in general use and which are a matter of preference for any given installation. 'I'he mechanism illustrated l diagrammatically hy the parts 39, 58, 60 and 6I is fully disclosed in the Malcolm E, Henning api plication for patent, Serial No. 575,278, filed Nomally open thermal actuated vember 16, 1931. My delayed' action oilvalve switch works eiectively in the circuit where such parts are provided and operates equally well whether the oil is pumped by the burner or some i other motor or flows by gravity from the oil reservoir to the burner. l

'I'he oil valve circuit will be opened by the contact 38 leaving the contact 46, but cannot be closed again because of the contact 38 being held from the contact 44 by the extension 6l (dotted line position). When the safety switch cuts, out, however, the armature 24 will raise so that thev contact 38 can re-engage the contact 44 for proper operation of the device whenever the safety switch is reset. Thus neither fuel nor igniter energization can be re-supplied after combustion fails until the cause of combustion failure has been remedied and the safety switch reset.

Some changes may be made in the construction and arrangement of the parts of my devicev without departing from the real spirit and purpose of my invention, and it is my' intention to cover by my claims, any modified forms of structure or use of mechanical equivalents, which may be reason .ably included within their scope.

I claim as my invention: 1. A control system for an atomizing oil burner having a motor driven atomizing fluid supply means comprising an ignition means, a magnetic oil valve which is opened when energized, a nor'- warp switch, which` when closed energizes said magnetic valve, an electric heater for actuating combustion responsive switching mechanism havins a ser or contacts which is closed in the absence of combustion and a second set of contacts which is closed in the presence of combustion, a thermostatic control switch and electrical means interconnecting the foregoing elements and operating upon closure ,of the control switch to 1) energize the blower motor, the ignition means and the electric heater, (2)v the warp switch closes energizing the oil valve and (3) upon combustion being established the ilrst set of contacts of the combustion responsive switching mechanism opens to de-energize the ignition. means and the electric heater and the second set of contacts closes to maintain the oil valve energized.

2. A control system for an atomizing oil burner having a motor .driven atomizing fluid supply means comprising an ignition means,-a magnetic oil valve which is opened when energized, a normally open thermal actuated warp switch. which when closed energizes said magnetic valve, an electric heater for actuating said warp switch, a combustion responsive switching mechanism having two sets of contacts, one closed in the absence of combustion and the other closed in the presence of combustion, a thermostatic control switch and electrical means interconnecting the foregoing elements and operating upon closure of the ABRAHAM LINCOLN RUBEL.

said warp switch, a 

